1. Field of the Invention
This invention relates generally to airtight containers and more particularly to compacts adapted for holding, storing, or packaging ultramoist powders and materials such as water-based cosmetics; powders; emulsions, creams, and other semi-solid or paste-type items.
2. Description of the Prior Art
For many storage applications, it is extremely undesirable to allow the stored material to either absorb moisture from the ambient surroundings or to lose moisture to these surroundings. Typical examples are cosmetics. Some cosmetics come in a dry, powder form and must maintain this powdery form in order to be used properly. If exposed to the air for extended periods, the powder will absorb moisture and begin to "cake", thereby losing its powdery consistency. Consequently, these cosmetics can no longer be used as intended.
The reverse situation is also true. Some cosmetics come in "supermoisturized" and must maintain this supermoist form in order to be used properly. If exposed to the air for extended periods, the material will lose moisture to the air, thereby losing its supermoist consistency. Consequently, these cosmetics can no longer be used as intended.
To prevent these undesired occurrences, the materials are stored in airtight containers. Compacts and other containers having airtight closures are known in the prior art. As illustrated in U.S. Pat. Nos. 4,454,889 and 5,186,318, the prior art shows an airtight seal formed by deformation of the inner surface of a base or closure member of the compact when that member is brought into contact with an opposing member of the compact.
Although these prior art containers do provide an airtight seal, in use they have a major disadvantage. To both achieve and undo the airtight seal requires application of significant force to close and open the compact, respectively. During the application of this sizable force, injuries may result to the user; broken nails and abrasions are common. Furthermore, when undoing the airtight seal, the applied force often causes some of the stored material to fly out of the container, thereby wasting that flying material and possibly staining or otherwise damaging surfaces upon which that flying material lands.
Thus, there is a need for a compact or other container with an airtight closure that requires less force to both achieve and undo the airtight seal.